Tire building former having cylindrical and toroidal configurations

ABSTRACT

A tire-building former having radially and axially movable supporting elements to provide a tire-building surface which is rigid in both cylindrical and toroidal configurations of the former specifically to facilitate the building of radial-ply tires.

United States Patent Inventor Appl. No.

Filed Patented Assignee Priority Noel Nehout Montlucon Allier, France621,855

Mar. 9, 1967 Sept. 21, 1971 The Dunlop Company Limited London, EnglandMar. 1 1, 1966 France TIRE BUILDING FORMER HAVING CYLINDRICAL ANDTOROIDAL CONFIGURATIONS 16 Claims, 20 Drawing Figs.

US. Cl 156/415, 156/417 Int. Cl ..B29h17/06, 82% 17/16, 32% 17/26 Fieldof Search 156/414, 415, 417, 420

References Cited UNITED STATES PATENTS 3/1930 Palmer 10/1966 Johannes10/1968 Eckenniler et :11. 11/1968 Pacciarini et al. 12/1969 Frazier3/1969 Caretta et al.

FOREIGN PATENTS 2/1900 Switzerland Primary Examiner-Benjamin A. BorcheltAssistant Examiner-Stephen C. Bentley A!t0rney Rauber 8:. LazarABSTRACT: A tire-building former having radially and axially movablesupporting elements to provide a tire-building surface which is rigid inboth cylindrical and toroidal configurations of the former specificallyto facilitate the building of radial-ply tires.

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PATENTEDSEPEI 1911 v 3507'. 55s SHEET 11 or 6 PATENTED Sim 1911 SHEET 5BF 6 PATENTEU SW21 l9?! SHEET 8 OF 6 Q N .U H \g TIRE BUILDING FORMERHAVING CYLINDRICAL AND TOROIDAL CONFIGURATIONS This invention relates totire-building apparatus and it is an object of the invention to providea new or improved construction of such apparatus.

According to the invention there is provided tire-building apparatuscomprising a radially expandable and contractable tire-building formerhaving a support surface movable between a radially contractedcondition, in which it is substantially cylindrical, and a radiallyexpanded condition, in which it is substantially toroidal, said surfacecomprising the radially outer periphery of a plurality of sets ofcircumferentially spaced-apart support segments each of which setscomprises at least three segments with adjacent segments in each setbeing pivotally linked together and operating means being provided tomove each set of segments radially outwardly or inwardly relative to thecentral longitudinal axis of the former.

Preferably three segments are provided in each set of segments, saidthree segments comprising a central segment disposed symmetrically aboutthe midcircumferential plane of the former, and two lateral segments,each one of which is pivotally connected to an axial end of the centralsegment for free pivotal movement about said central segment, adjustablelimit stops being provided to limit the axially inward degree of suchpivotal movement of the lateral segments.

The operating means is preferably operably connected to the central linkof each set of segments and comprises a pair of cooperating linksassociated with each set of segments, an axially inner end of each linkbeing secured to the central segment and an axially outer end of eachlink being mounted for movement axially of the former with the linksbeing so arranged that axial movement of the axially outer ends thereofproduces a substantially radial movement of the axially inner endsthereof.

In one construction the axially inner ends of each pair of links areformed with a plurality of cooperating gear teeth set along an arcuatepath on each link and the axially outer end of each link is pivotallyconnected to a nut engaged upon a common screwthreaded shaft providedwith two screw-threaded portions, the pitches of each of which are equalbut are in an opposed sense whereby rotation of the shaft causessymmetrical axial movement of the nuts along the shaft either towards oraway from one another.

There may also be provided a plurality of support flanges arranged incircumferentially spaced-apart relationship adjacent the axially outerends of the lateral segments, said flanges being movable radiallyinwardly and outwardly relative to the central longitudinal axis of theformer and said flanges being detachably mounted upon a plurality ofassociated support bars extending axially of the former, one such flangebeing mounted adjacent each end of each associated bar. In thisconstruction inflatable means are provided to act upon the support barsto move them in a radially outward direction, said inflatable meanscomprising an annular inflatable chamber located adjacent each end ofthe support bars and radially inwardly thereof.

One embodiment of the invention will now be described in more detailwith reference to the accompanying drawings wherein:

FIGS. 1 to 4 are somewhat diagrammatic half-radial sections through thetire-building former showing cylindrical and toroidal configurations ofthe support segments and also showing how the former can accommodate andshape different carcass sizes.

FIG. 5 is a side elevation of a part of the former periphery showing thesupport segments.

FIG. 6 is an exploded radial section showing one set of support segmentsin the toroidal configuration and also showing parts of the operatinglinks.

FIG. 7 is a sectional view on the line VII--VII of FIG. 6.

FIG. 8 is a partial side sectional view of the central support segmentsshowing their means of attachment to the operating links.

FIG. 9 is a partial side sectional view of the central support segmentsand operating links in their retracted position in engagement with thesupport bars.

FIG. 10 is a radial view of one set of support segments in the toroidalconfiguration showing the provision of cover plates.

FIG. 11 is a plan view of two sets of support segments in the toroidalconfiguration showing the cover plates in more detail.

FIG. 12 is a side elevation of the support segments and cover plates.

FIG. 13 is a view on the line XIII-XIII of FIG. 10.

FIG. 14 is a radial view of one set of support segments and cover platesin the cylindrical configuration.

FIG. 15 is a plan view of a plurality of the sets of support segmentsshowing the cover plates.

FIG. 16 is a half radial cross section of the apparatus showing theformer in the cylindrical configuration.

FIG. 17 is a similar half radial cross-sectional view showing the formerin the toroidal configuration.

FIG. 18 is a partial sectional view of the line XVIlI-XVIII of FIG. 16.

FIG. 19 is partially a plan view and part cross section on the lineXIXXIX of FIG. 16 showing the shape of the support bars.

FIG. 20 is a side elevation showing the former main hub and axle and itsprincipal control elements.

In this construction the tire-building former has a building surfacewhich can be shaped from a substantially cylindrical configuration, forthe building thereon of a tire carcass, to a toroidal configuration, forthe addition to the shaped carcass of breaker and tread components tocomplete the building of the unvulcanized tire. The building supportsurface of the former comprises a plurality of circumferentiallyspaced-apart sets of support segments and FIGS. 1 to 4 show an assemblyof one such set of three support segments, the central segment 10 ofwhich is symmetrical about the midcircumferential plane of the buildingformer and upon either side of which is located a lateral segment 11pivotally connected thereto by means of a pivot pin 12. The extremeaxially inward position of these lateral segments 11, as shown in FIGS.1 and 3, relative to the central segments 10 can be adjusted by means ofscrew stops 13 which abut against the radially inner surface of thecentral segment 10.

An annular diaphragm 14 of elastomeric material such as rubber extendsaround the radially outer surfaces of all of the lateral and centralsegments, the axial edges of the diaphragm being secured to the axiallyouter extremities of the lateral segments 11 as shown in more detail inFIG. 6. The diaphragm 14 thus covers the whole of the building supportsurface of the former whilst the radially outer surface of the diaphragmitself forms a continuous surface upon which the elements of the tirecan be assembled during the tire-building operation.

Located nearer to the central longitudinal axis of the building formerand parallel thereto there are provided a plurality of elongated supportbars 15, the radially outer surfaces of which define a cylindricalsurface. Each such support bar 15 has located thereon symmetricallyabout the midcircumferential plane of the former, support flanges 16which are themselves substantially Lshaped, the flanges being adjustablylocatable along the support bars 15 by means of pin and socketconnections 17 to obtain an axial spacing of the flanges dependent uponthe width of the tire to be built upon the former. These L-shapedflanges are removable from the support bars and replaceable as desiredby flanges having any suitable desired radial height dependent upon thediameter of the tire to be built, differing dimensions in the axial andradial directions being represented on FIGS. 1, 2 and 3, 4 respectivelyas A, B, C, D and Al, B1,C1, D1. The radially outermost surfaces of eachset of support flanges 16 has an annular elastic diaphragm 18 (see FIGS.16 and 17) secured thereto to provide a continuous building surface andwhich also acts to retract the flanges, and hence the support bars,radially inwardly.

As is clearly shown in FIGS. 1 to 4, both the lateral and centralsupport segments have a curved radially outer surface and, referring toFIG. 5, the axially inner end of each lateral segment 11 is bifurcatedat 19 for pivotal connection to the corresponding axial end of theassociated central segment by means of the pivot pin 12. Referring nowto FIG. 6 it is seen that each axial edge of the rubber diaphragm 14 isformed with an integral annular T-shaped head 20 engaging within a partof the axial extremities of the lateral segments 11 and secured inposition by means of clamping plates 21 and associated screws 22.

Radial movement of each set of support segments is effected by means ofa pair of operating links 23, the axially inner extremities of which areshown in FIG. 6, and which are pivotally mounted by pivot pins 24between two rectangular plates 25 having projections 26 engageablewithin a corresponding slot 27 in the central segment 14), the plates 25being secured thereto by a suitable bolt 23 (see FIG. 8).

The ends of the operating links 23 at the positions at which they arelocated in between the plates 25 are formed with interengaging gearteeth 29 set along an arcuate path. On either side of the two plates 25there are provided washers 30 of a large thickness through which thepivot pins 24 pass and in the fully retracted position of the segmentsthese washers bear upon the radially outer surfaces of the cooperatingsupport bars 15.

In order to present a more continuous radially outer building surfaceupon the support segments, suitably shaped, thin metal support plates 31and 32 are secured to both the central and lateral segmentsrespectively, the disposition and configuration of these plates beingshown in more detail in FIGS. 10 to 15.

FIGS. 16 and 17 show in more detail the arrangement of the completebuilding former wherein it can be seen that the radially outwardmovement of the support bars 15 is limited by the engagement of theiraxially outer ends with cooperating flanged limit stops 33 secured tothe hub 34 of the former. Radial movement of the support bars 15 isproduced by inflation of two symmetrically located annular inflationchambers 35 located radially inwardly of the support bars and mountedupon annular support surface 36 rigid with the hub 34. A detail of thelimit stops 33 is shown in FIG. 19 wherein it will be seen that eachsupport bar 15 has a narrower central section 15a than itsend sectionswhereby each pair of operating links 23 which effect movement of anassociated set of support segments can be located between adjacentsupport bars.

The radial displacement of the support bars 15 has as a first objectprovision for the radial expansion or retraction of the L-shaped supportflanges 16 according to whether the flanges are required to be in acarcass building position as shown in FIG. 16 or removed therefrom toallow shaping of the carcass to the toroidal configuration as shown inFIG. 17. A secondary object of the radial movement of the support barsis to assist in giving an initial radially outward movement to theoperating links 23 by virtue of the radially outer surfaces of thesupport bars 15 lifting the links radially outwardly by engagement ofsuch surfaces with the enlarged washers 30.

As will be seen in FIGS. 16 and 17, each operating link 23 is of curvedelongated form, the axially outer extremity of which is pivotallymounted upon an annular element 37 slidable axially along a smooth shaft38 of the former. Each such element 37 is connected to a nut 39 inscrew-threaded engagement with a screwed central shaft 40 of the formerby means of a key 41 passing through an axially extending slot 412formed in the smooth shaft 38. The central screw-threaded shaft 4-0 isformed with two screw-threaded portions, the pitches of each of whichare equal but in an opposed sense, whereby rotation of this shaft allowssymmetrical axial approach and separation of the nuts 39 and therebycauses symmetrical radial movement of the axially inner ends of theoperating links 23.

FIG. 20 shows a general arrangement of the principal control elements ofthe building former wherein can be seen the central screwed shaft 40 ofthe former located coaxially within the hub 34 and having an axiallyextending bore 43 formed therein for connection to the annularinflatable chambers 35. This bore 43 communicates, in a pedestal 44 ofthe former, with a suitable regulating valve 45 for pressurizing fluid,rotary sealing joints 46 being provided at that end of the hub 34 whichis mounted in the pedestal 44.

Rotation of the hub 34 is effected by means of an electric motor 47 anda chain drive 48 to a toothed sprocket 49 mounted upon the hub whilst afurther motor (not shown) connected by a further chain drive 50 andclutch mechanism 51 is provided to rotate the central screwed shaft 40independently of the hub if desired. Thus when the hub is stationary andthe clutch 51 engaged to drive the screwed shaft 40, the nuts 39 are runeither away from or towards one another to effect movement of theoperating links 23 as required and thus effect radial movement of thesupport segments from their cylindrical configuration to their toroidalconfiguration and vice versa.

The full shaping of the former from the cylindrical to the toroidalconfiguration is carried out as follows. The regulator valve 45 isopened to inflate the annular chambers 35 thereby moving the supportbars 15 radially outwardly until they abut against their limit stops 33.At the same time the screwed shaft 40 is rotated to cause the operatinglinks 23 to move towards one another, the initial movement of the linksbeing assisted by the engagement of the support bars 15 with the washers30 and the rotation of the shaft 40 is stopped when the support barsabut their limit stops, this position being shown in FIG. 16.

In this position the support segments are still in their cylindricalconfiguration and the radially outer surface thereof is coplanar withthe radially outer surfaces of the L-shaped support flanges 16. In thisconfiguration of the former the carcass is then built thereon and aftercompletion the shaping to the full toroidal configuration is commencedas follows:

Firstly the chambers 35 are deflated to allow the support flanges 16 andbars 15 to retract radially inwardly away from the carcass under theelastic influence of the diaphragrns 18. At the same time rotation ofthe screwed shaft 40 is recommenced to cause the operating links 23 toapproach one another and move the support segments radially outwardly toexpand the carcass to its toroidal configuration as shown in FIG. 17. Aswill be seen the central segments 10 act upon the crown region of thecarcass whilst the lateral segments 11 act upon the shoulder andsidewall regions, the degree of shaping being limited by the degree towhich the lateral segments 11 can swing axially inwardly about theirpivot pins 12 before the adjustable screw stops l3 abut the centralsegments.

When the final diameter of the crown region of the carcass isaccomplished, it is then possible to add the breaker and treadcomponents of the tire to complete the tire-building operation. Afterthis step the screwed shaft 40 is rotated in the opposite direction towithdraw the support segments radially inwardly. The segments return totheir cylindrical configuration under the influence of the elasticdiaphragm l4 and the lateral segments 11 are guided to thisconfiguration by the engagement of the extremities of the clampingplates 21 with the L-shaped support flanges 16 until the position shownin chain dot lines in FIG. 17 is reached whereupon the shapedunvulcanized tire can be removed from the former.

Tire-building apparatus constructed in accordance with the inventiongreatly facilitates the building of radial ply tires wherein it isnecessary that the built carcass is shaped to substantially the finaldesired diameter before the breaker and tread components of the tire areadded. The provision of a tire support surface which is rigid in boththe cylindrical and toroidal configurations of the former enables boththe carcass plies of the breaker and tread components of the tire to beassembled accurately upon the former and obviates the possi bility ofaccidental displacement of the cord angle of the carcass and breakercomponents.

I claim:

1. Tire-building apparatus comprising a radially expandable andcontractable former which comprises a plurality of sets of rigid supportsegments circumferentially spaced apart around the periphery of theformer, the outer surface of each segment being curved in a planecontaining a radius and the axis of the former, the outer periphery ofthe segments forming a supporting surface and each set comprising atleast three rigid segments, axially spaced-apart pivots connectingadjacent segments in each set together and operating means to move thesets of segments between a radially outer position in which the saidradially outer periphery is a substantially toroidal supporting surfacein which each set of segments has a horseshoe configuration and aradially inner position in which the said radially outer periphery is asubstantially cylindrical supporting surface in which the segments ofeach set are arranged substantially in a straight line.

2. Tire-building apparatus as claimed in claim 1 wherein three segmentsare provided in each set of segments, said three segments comprising acentral segment disposed symmetrically about the midcircumferentialplane of the former and two lateral segments each one of which ispivotally connected to an axial end of the central segment.

3. Tire-building apparatus as claimed in claim 2 wherein the lateralsegments in each set of segments are freely mounted for pivotal movementabout the central segment, adjustable limit stops being provided tolimit the axially inward degree of such pivotal movement of the lateralsegments.

4. Tire-building apparatus as claimed in claim 2 wherein a plurality ofcover plates are secured to the radially outer surfaces of some at leastof the lateral and central segments to provide a substantiallycontinuous peripheral surface circumferentially of the former.

5. Tire-building apparatus as claimed in claim 4 wherein an annularelastic diaphragm is secured to the segments radially outwardly of saidcover plates to provide a continuous circumferential surface extendingaxially across the full overall width of each set of segments.

6. Tire-building apparatus as claimed in claim 2 wherein said operatingmeans is operably connected to the central segments of each set.

7. Tire-building apparatus as claimed in claim 6 wherein said operatingmeans comprises a pair of cooperating links associated with each set ofsegments, an axially inner end of each link being secured to the centralsegment and an axially outer end of each link being mounted for movementaxially of the former and the links being so arranged that axialmovement of the axially outer ends thereof produces a substantiallyradial movement of the axially inner ends.

8. Tire-building apparatus as claimed in claim 7 wherein the axiallyouter end of each link is pivotally connected to a nut engaged upon acommon screw-threaded shaft provided with two screw-threaded portions,the pitches of each of which are equal but are in an opposed sensewhereby rotation of the shaft causes symmetrical axial movement of thenuts along the shaft either towards or away from one another.

9. Tire-building apparatus as claimed in claim 7 wherein the axiallyinner ends of each pair of links are formed with a plurality ofcooperating gear teeth set along an arcuate path of each link.

10. Tire-building apparatus as claimed in claim 2 wherein a plurality ofsupport flanges are provided arranged in circumferentially spaced-apartrelationship adjacent the axially outer ends of the lateral segments,said flanges being movable radially inwardly and outwardly relative tothe central longitudinal axis of the former.

ll. Tire-building apparatus as claimed in claim 10 wherein said flangesare detachably mounted upon a plurality of associated support barsextending axially of the fonner, one such flange being mounted adjacenteach end of each associated bar.

12. Tire-building apparatus as claimed in claim 11 wherein an annularelastic diaphragm is secured around the radially outer peripheralsurfaces of said flanges at each end of the former to urge the flangesradially inwardly.

l3. Tire-building apparatus as claimed in claim 11 wherern inflatablemeans are provided to act upon the support bars to move them in aradially outward direction.

14. Tire-building apparatus as claimed in claim 13 wherein saidinflatable means comprises an annular inflatable chamber locatedadjacent each end of the support bars radially inwardly thereof.

15. Tire-building apparatus as claimed in claim 11 wherein the supportbars are engageable with the operating links whereby radially outwardmovement of the support bars assists, at least partially, in theradially outward movement of the axially inner ends of the links.

16. Tire-building apparatus as claimed in claim 11 wherein stops areprovided to limit the degree of radially outward movement of the supportbars.

2. Tire-building apparatus as claimed in claim 1 wherein three segmentsare provided in each set of segments, said three segments comprising acentral segment disposed symmetrically about the midcircumferentialplane of the former and two lateral segments each one of which ispivotally connected to an axial end of the central segment. 3.Tire-building apparatus as claimed in claim 2 wherein the lateralsegments in each set of segments are freely mounted for pivotal movementabout the central segment, adjustable limit stops being provided tolimit the axially inward degree of such pivotal movement of the lateralsegments.
 4. Tire-building apparatus as claimed in claim 2 wherein aplurality of cover plates are secured to the radially outer surfaces ofsome at least of the lateral and central segments to provide asubstantially continuous peripheral surface circumferentially of theformer.
 5. Tire-building apparatus as claimed in claim 4 wherein anannular elastic diaphragm is secured to the segments radially outwardlyof said cover plates to provide a continuous circumferential surfaceextending axially across the full overall width of each set of segments.6. Tire-building apparatus as claimed in claim 2 wherein said operatingmeans is operably connected to the central segments of each set. 7.Tire-building apparatus as claimed in claim 6 wherein said operatingmeans comprises a pair of cooperating links associated with each set ofsegments, an axially inner end of each link being secured to the centralsegment and an axially outer end of each link being mounted for movementaxially of the former and the links being so arranged that axialmovement of the axially outer ends thereof produces a substantiallyradial movement of the axially inner ends.
 8. Tire-building apparatus asclaimed in claim 7 wherein the axially outer end of each link ispivotally connected to a nut engaged upon a common screw-threaded shaftprovided with two screw-threaded portions, the pitches of each of whichare equal but are in an opposed sense whereby rotation of the shaftcauses symmetrical axial movement of the nuts along the shaft eithertowards or away from one another.
 9. Tire-building apparatus as claimedin claim 7 wherein the axially inner ends of each pair of links areformed with a plurality of cooperating gear teeth set along an arcuatepath of each link.
 10. Tire-building apparatus as claimed in claim 2wherein a plurality of support flanges are provided arranged incircumferentially spaced-apart relationship adjacent the axially outerends of the lateral segments, said flanges being movable radiallyinwardly and outwardly relative to the central longitudinal axis of theformer.
 11. Tire-building apparatus as claimed in claim 10 wherein saidflanges are detachably mounted upon a plurality of associated supportbars extending axially of the former, one such flange being mountedadjacent each end of each associated bar.
 12. Tire-building apparatus asclaimed in claim 11 wherein an annular elastic diaphragm is securedaround the radially outer peripheral surfaces of said flanges at eachend of the former to urge the flanges radially inwardly. 13.Tire-building apparatus as claimed in claim 11 wherein inflatable meansare provided to act upon the support bars to move them in a radiallyoutward direction.
 14. Tire-building apparatus as claimed in claim 13wherein said inflatable means comprises an annular inflatable chamberlocated adjacent each end of the support bars radially inwardly thereof.15. Tire-building apparatus as claimed in claim 11 wherein the supportbars are engageable with the operating links whereby radially outwardmovement of the support bars assists, at least partially, in theradially outward movement of the axially inner ends of the links. 16.Tire-building apparatus as claimed in claim 11 wherein stops areprovided to limit the degree of radially outward movement of the supportbars.